Process of recovering sulfur.



W. FELD 6: A. JAHL.

PROCESS OF BEGOVEBING SULFUR. run-non rILnn mm. us, 1900.

927,342. Patented July 6, 1909.

WITNESSES INVEA/TU/is Walther Fold and Anton Jahl, 1

STATES PATENT OFFICE.

WALTHER FELD, 0F ZEHLENDORI", AND AIlTON JAHL, OF HONNINGEN-ON-THE-RHINE,

GERMANY; SAID JAHL ASSIGNOR TO SAID FELD.

moans o1;- anoovnnmo comma.

Specification 0! Letter. Patent.

Patented July 6, 1909.

To all whom it may concern:

Be it known that we, WALTHER FnLn, a subject of the King of Piussia and the GermanEm )eror, of 14Hauptstrasse, Zehlendorf, in the Kingdom of Prussia and German Empire, and ANTON Jana, a sub'ect of the Em eror of Austria-Hungary am the King of ohemia,.of l-lonningen-on-thc-lthine, in the Kingdom of Prussia and German Em pire, have invented new and useful Improvements in Processes of Recovering Sul ur, of which the following is a specification.

The object of this invention is to effect the oxidation of sulfureted hydrogen by means of sulfur-dioxid, according to the reaction so that sulfur of good quality is obtained in much larger quantity than hitherto.

Accordmg to this invention, the reaction, in accordance with the aforesaid e uation, is effected b passing the ases t irough a liquid, or t rough liquids, w 'ch has, or have, the power of dissolvin the sulfur produced by the reaction, so t lat the formation of thio-sulfate, or poly-thionic acids is almost completely prevented. The most suitable liquids which we have discovered for the orpose are the socalled tar-oils obtained rom the distillation of organic matter, and, consisting of mixtures of hydrocarbons and they are especially efficient if they be preheated. The suitabilit Y of the said tar-oils to the purpose is we be ieve due to the presence in the said tar-oils of organic nitrogenous substances, such as the aromatic amins, amids, nitriles, thio-amids and the like, and the compounds of the ali hatic series, which substances combine wit the sulfur-dioxid, and form compounds which decompose-again on the solvent being heated. While the recess is usually facilitated by moderately eating the reacting liquid, it may be carried out at any convenient temperature. Thus it has been successful at a temperature even below 10 C. on the one hand, and above 100 C. on the other hand. A basic substance such as inorganic ammonium bases, the basic and sulfurous compounds of aluminum, and, undercertain precautions, basic magnesium and ammonium com ounds, and their sulfites, may be 'adde to the said liquid. When sulfites are added care should be taken that the reacting liquid is he t acid, as otherwise thio-sulfate and poly-t ionic acids will be formed. In using such basic substances, it often occurs that, after repeated use, the activity of the liquid decreases, owing to the formation of ox -acids of sulfur,for instance, sulfates. The ases can be regenerated, by decomposing such sulfatcsby the addition of an oxid, hydrate, carbonate, sulfid or sulfite of the alkalies, alkaline earths, ammomum magnesium, or aluminum. By using allraline earths, insoluble sulfates are produced, and, in this case, it is preferable to effect the regeneration of the active means after the removal of the sulfur. The sulfur is allowed to crystallize out and the solvent se arated from the sulfur and containing the su fate of the tar bases, is treated with milk of lime, or with calcium sulfite, the base, or its sulfite, being regenerated.

The following is an example of a way of carrying out this invention in which so-called heavy tar-oil is used as the reacting liquid. In order to increase the rapidity of the reaction, a further amount of tar ases ma be added to the oil, and in order to bind sul uric acid which may exist in the sulfur-dioxid, a substance, such, for instance, as sodium carbonate, is added. The oil thus prepared is then heated to 40 centigrade and at the same time sulfur-dioxid and sulfureted-hydrogen, or gases containing them, are introduced. In order that no sulfureted hydrogen shall escape, so much sulfur-dioxid is supplied that at least one molecular proportion of sulfur-dioxid is present for each two molecular proportions of sulfureted hydroen. An excess of sulfur-dioxid does no arm, as the li uid absorbs the sulfur-dioxid. If desired the iquid may first be saturated with sulfur-dioxld and then sulfureted hydrogen be introduced, these operations being repeated alternately until the liquid is saturated with sulfur and the sulfur crystallizes out. The liquid becomes so strongly heated by the reaction that finally the water gener ated in the reaction is evaporated. The oxidation of the sulfureted hydrogen is complete even when it is very dilute. The reaction is preferably stopped as soon as the liquid becomes pulpy and contains for every 100 parts thereof say from 50, to 60, parts of sulfur, partly dissolved and partly separated in crystalline form. After the introduction of the gases is stopped, the oil containing the sulfur is allowed to cool in crystallizing vessels, and the sulfur is-obtained in pure crysof separating from them the adhering oil,

the are washed with a suitable medium,

,suc for instance, as steam.

If it be desired toavoid loss of sodium in the form of sodium sulfate, the oil is used without the addition of sodium carbonate and, after the reaction is finished, the sulfur is allowed to crystallize. The mother liquor, after being mixed with the liquor obtained in Washing the sulfur by steam, is treated with milk of lime. Insoluble gypsum se arates while the re enerated tar bases are issolved b the oi. If the gases to be deprived 0 sulfur contain also ammonia, it is not necessary to add to the reacting liquid a binding medium for the sulfuric acid but in this case it is necessary to rovide means to keep the liquid acid by su ur dioxid. For the same purpose it is then preferable to use as the reaction liquid a fraction of the tar distillation which is rich in phenols and therefore possesses a weak acid character. In place of tar-oils, oils obtained in the distillation of ordinary, or brown, coal, shale, peat, bones and the like can also be used as the said liquid. Carbolic acid can also be used as the reaction li uid, tar bases being added for the purpose 0 increasing the rapidity of the reaction. If desired, ammonia gasescan be passed through the li uid together with the sulfur-dioxid and en uretedhydrogen, or the gases may be passed through in succession.

' The accom anying drawing illustrates diagrammatica y an apparatus suited to the urposes of our invention but we do not imit ourselves to the use of this apparatus.

A, is a vessel which may be like an ordinary gas washer. The ases to betreated enter at a and leave at The tar oils (or other liquid, or liquids having the power of dissolving sulfur) enter at c and leave at d. The liquor which has taken up the sulfur runs into the vessel E, in which 1t stands and cools and the sulfur crystallizes out. From the vessel E, the liquor, containing the sulfur crystals is discharged into the centrifugal separator F, and the-liquor, after bein separated from the sulfur in this separator runs into the stirring tank G, by the pipe f. The

"pump H, pumps the liquor again to the washer through the pipe h. We may use two, or more, washers A and vessels E, if desired so that the liquor containing sulfur can be fed into one while liquor in the other, or others, is standing to allow the sulfur to crystallize.

In order to regenerate the bases with lime, if necessa a stirring tank I is provided with a ta K, containing lime, above. In this case the liquor, instead of running directly from the separator F to the tank G, is collected in tank I, lime isadded and the liquor, after having been stirred for some time, is allowed to clear. The clear liquor, containing the regenerated bases is then run by pipe n. to tank G. The mud may be removed by m. Pipe 1', leadin into the liquor in G is used for treating theIiquor in Gwith sulfur dioxid.

We claim:

1. A process for obtaining sulfur from sulfur-dioxid and sulfureted hydrogen, consisting in passing these gases through liquid having the power of dissolving the su fur as it separates.

2. A process for obtaining sulfur from sulfur-dioxid and sulfureted h drogen, consisting in passing these gases tlirou h tar distillation products of the character ereinbefore set forth.

3. A process for obtaining sulfur from sulfur-dioxid and sulfureted hydrogen consisting in passing these gases through heated liquid having the power of dissolving the sulfur as it separates.

4. A process for obtaining sulfur from sulfur-dioxid and sulfureted hydro 'en, consisting in passing these gases throug h heated tar distillation products of the character hereinbefore set forth.

5. A process for obtaining sulfur from sulfur-dioxid and sulfureted hydrogen consisting in passing these gases through li uid having the power of dissolving the su fur as it separates, the said liquid containing a substance of the character described capable of uniting with a portion of the sulfur compounds present to produce a compound adapted to be decomposed on being heated in t e presence of li uid.

6. process for o taining sulfur from sulfur-dloxid and sulfureted hydrogen'consisting in passing these gases through li uid having the power of dissolving the su ur as it separates, the said liquid containing an organic substance of the character described capable of uniting with a portion of the sulfur compounds present to produce a com-' ound adapted to be decomposed on being eated in t e presence of liquid.

7. A process for obtaining sulfur from sulfur-dioxid and sulfureted hydro en, consisting in passing these gases, and a o ammonia gas, through liquid having the power of dissolvin sulfur as it separates, the said liquid being ept feebly acid.

8. A process for obtaining sulfur from sulfur-dioxid and sulfureted hydrogen, consisting in passing said gases through liquid having the ower of dissolving sulfur as it separates, w ich liquid contains a basic substance of the character described capable of uniting with a portion of the sulfur compounds resent to (produce compounds, some of w 'ch are, an others whic are not adapted to be decomposed on being heated in the presence of liquld.

9. A process for obtaining sulfur from sulfur-dioxid and sulfureted hydrogen, consisting in passing said gases throulgh liquid having the power of dissolving su ur as it separates, w of the character described capable of uniting with a portion of the sulfur compounds present to produce com unds, some of which are and others whic are not adapted to be decomposed on bein heated in the presence of liquid and a so a substance adapted to prevent the formation of said compounds not adapted to be decomposed on being heated in the presence of liquld.

10. A process for obtaining sulfur from sul-.

fur-dioxld and sulfureted hydrogen, consisting inpassing these (gases through a liquid having the power of issolving the-sulfur as it separates, the said liquid containing a substance of the character described capable of uniting with a portion. of the sulfur compounds present to produce a compound adapted to be decomposed on being heated in t e presence of liquid, recovering the sulfurfrom the said com ound and subsequently decomposing any sull ate formed by the combination of said substance with any sulfuric acid present in the gases .by treating the liquor with a compound of an alkaline earth w ich will bind the sulfuric acid and regenerate the substance.

ich liquid contains a basic substance 11. A process for obtaining sulfur from sulfur-dioxid and sulfureted hiyl drogen, consisting in passing these gases t rough an oil obtamed from the distillation of any suitable matter, said oil having the power of dissolving the sulfur as it separates.

12. Ina process for obtaining sulfur from sulfur-dioxid and sulfureted hydrogen b. passing these gases through a llquid whic as the power of dissolving sulfur as it sepa-,

rates and in which sulfates are formed during the process, the subjection of said sulfates to the action of a substance adapted to regenerate the bases, substantially as described.

13. In a process for obtaining sulfur from WALTHER FELD. ANTON J AHL.

Witnesses Loms VANDORN, J orm WALZEB. 

